Protein kinases play a critical role in the control of cell growth and differentiation. Aberrant expression or mutations in protein kinases have been shown to lead to uncontrolled cell proliferation, such as malignant tumour growth, and various defects in developmental processes, including cell migration and invasion, and angiogenesis. Protein kinases are therefore critical to the control, regulation, and modulation of cell proliferation in diseases and disorders associated with abnormal cell proliferation. Protein kinases have also been implicated as targets in central nervous system disorders such as Alzheimer's disease, inflammatory disorders such as psoriasis, bone diseases such as osteoporosis, atheroscleroses, restenosis, thrombosis, metabolic disorders such as diabetes, and infectious diseases such as viral and fungal infections.
One of the most commonly studied pathways involving kinase regulation is cellular signaling from receptors at the cell surface to the nucleus. Generally, the function of each receptor is determined by its pattern of expression, ligand availability, and the array of downstream signal transduction pathways that are activated by a particular receptor. One example of this pathway includes a cascade of kinases in which members of the Growth Factor receptor Tyrosine Kinases deliver signals via phosphorylation to other kinases such as Src Tyrosine kinase, and the Raf, Mek and Erk serine/threonine kinase families. Each of these kinases is represented by several family members which play related, but functionally distinct roles. The loss of regulation of the growth factor signaling pathway is a frequent occurrence in cancer as well as other disease states. Fearon, Genetic Lesions in Human Cancer, Molecular Oncology, 1996, 143–178.
The raf1 serine/threonine kinase can be activated by the known oncogene product ras. The raf kinase enzyme positively regulates cell division through the Raf/MEK/ERK protein kinase cascade. This activation is the result of cRaf1 catalyzed phosphorylation of the protein kinase, MEK1, which phosphorylates and activates the protein kinase. ERK phosphorylates and regulates transcription factors required for cell division. Avruch et al., TIBS, 1994 (19) 279–283. cRaf1 negatively regulates cell death by modulation of the activity of Bcl-2, a critical regulator of apoptosis. This regulation involves direct phosphorylation of Bcl-2 family members. Gajewski and Thompson, Cell, 1996 (87) 619–628.
These aspects of cRaf1-mediated regulation of cell proliferation require the kinase activity of cRaf1. It has also been reported that the reduction of Raf protein levels correlates with a reduction in tumor growth rate in vivo tumor mouse models. Monia, Johnston, Geiger, Muller, and Fubro, Nature Medicine, Vol. 2, No. 6, June 1996, 668–674. Inhibitors of the kinase activity of cRaf1 should therefore provide effective treatment for a wide variety of human cancers.
Activation of the MAP kinase signaling pathways represents an attractive target for tumor therapy by inhibiting one or more of the kinases involved. An additional member of the MAP kinase family of proteins is the p38 kinase, alternatively known as the cytokine suppressive drug binding protein or reactivation kinase, RK. Activation of this kinase has been implicated in the production of proinflammatory cytokines such as IL-1 and TNF. Inhibition of this kinase could therefore offer a treatment for disease states in which disregulated cytokine production is involved.
The signals mediated by kinases have also been shown to control cell growth, cell death and differentiation in the cell by regulating the processes of the cell cycle. Progression through the eukaryotic cell cycle is controlled by a family of kinases called cyclin dependent kinases (CDKs). The loss of control of CDK regulation is a frequent event in hyperproliferative diseases and cancer.
Inhibitors of kinases involved in mediating or maintaining particular disease states represent novel therapies for these disorders. Examples of such kinases include inhibition of Src, raf, and the cyclin-dependent kinases (CDK) 1, 2, and 4 in cancer, CDK2 or PDGF-R kinase in restenosis, CDK5 and GSK3 kinases in Alzheimers, c-Src kinase in osteoporosis, GSK-3 kinase in type-2 diabetes, p38 kinase in inflammation, VEGF-R 1–3 and TIE-1 and -2 kinases in angiogenesis, UL97 kinase in viral infections, CSF-1R kinase in bone and hematopoetic diseases, and Lck kinase in autoimmune diseases and transplant rejection.
The microbial-derived material referred to as “K-252a” is a unique compound which has gained significant attention over the past several years due to the variety of functional activities which it possesses. K-252a is an indolocarbazole alkaloid that was originally isolated from a Nocardiosis sp. culture (Kase, H et al. 39 J. Antibiotics 1059, 1986). K-252a is an inhibitor of several enzymes, including protein kinase C (PKC) which plays a central role in regulating cell functions, and trk tyrosine kinase. The reported functional activities of K-252a and its derivatives are numerous and diverse: tumor inhibition (See U.S. Pat. Nos. 4,877,776, 4,923,986, and 5,063,330; European Publication 238,011 in the name of Nomato); antII-insecticidal activity (See U.S. Pat. No. 4,735,939); inhibition of inflammation (See U.S. Pat. No. 4,816,450); treatment of diseases associated with neuronal cells (See U.S. Pat. Nos. 5,461,146; 5,621,100; 5,621,101; and WIPO Publication WO 94/02488, published Feb. 3, 1994 in the names of Cephalon, Inc. and Kyowa Hakko Kogyo Co., Ltd.); and treatment of prostate disease (See U.S. Pat. Nos. 5,516,771; and 5,654,427). K-252a also has been reported to inhibit IL-2 production (See Grove, D. S. et al., Experimental Cell Research 193: 175–182, 1991).
The reported indolocarbazoles share several common attributes. In particular, each comprises three five member rings which all include a nitrogen moiety; staurosporine (derived from Streptomyces sp.) and K-252a each further comprise a sugar moiety linked via two N-glycosidic bonds. Both K-252a and staurosporine have been extensively studied with respect to their utility as therapeutic agents. The indolocarbazoles are generally lypophilic, which allows for their comparative ease in crossing biological membranes, and, unlike proteinaceous materials, they manifest a longer in vivo half-life.
Although K-252a is normally derived from culture media via a fermentation process, the total synthesis of the natural (+) isomer and the unnatural (−) isomer, in which the three chiral carbons of the sugar have the opposite configurations, has been achieved (See Wood et al., J. Am. Chem. Soc. 117: 10413, 1995, and WIPO Publication WO 97/07081). However, this synthesis is not practical for commercial use.
In addition to the indolocarbazole alkaloids represented by K-252a and staurosporine, synthetic small organic molecules which are biologically active and known as fused pyrrolocarbazoles have been prepared (See U.S. Pat. Nos. 5,475,110; 5,591,855; 5,594,009; 5,705,511; and 5,616,724).
Fused isoindolones which are non-indole-containing molecules that can be chemically synthesized de novo are also known (See U.S. Pat. No. 5,808,060 and WIPO Publication WO 97/21677).
Certain bis-indolylmaleimide macrocyclic derivatives have also been reported (See for example U.S. Pat. Nos. 5,710,145; 5,672,618; 5,552,396 and 5,545,636).
Sugar derivatives of indolopyrrolocarbazoles also have been reported (see WIPO Publication WO98/07433).
Thus, there is a need for novel classes of compounds which demonstrate activity toward receptor and non-receptor types of protein kinases. It has been discovered that a class of compounds, referred to herein as cyclic substituted fused pyrrolocarbazoles and isoindolones, are useful as agents for the regulation of protein kinase. The present invention is therefore directed to, inter alia, their use as therapetic agents for the treatment of the foregoing disorders, as well as other important ends.